RAIL chiefs yesterday slated an American academic who scaled the landmark Forth Bridge for kicks.

Bradley Garrett got inside the famous red-girder crossing before climbing to the top of the 360ft towers as passenger trains thundered below him.

The Forth stunt is revealed in a book by Garrett, who calls himself an “urban explorer”, but transport police and rail safety campaigners accuse him of putting lives at risk by encouraging copycat attempts.

Network Rail, who own the 123-year-old bridge, have slated the book, which features a stunning photo of Garrett, 32, high up on the Victorian structure.

A spokesman said: “It is very disappointing that a publisher is trying to profit from something as hazardous and illegal as trespassing on the railway. The Forth Bridge is a busy structure, which is in use 24 hours a day, and attempting to climb it illegally is as stupid as it is dangerous.

Garrett, an Oxford University tutor, hit the headlines in April last year when he scaled the 1000ft Shard building in London while it was still under construction – prompting an immediate review of security at the site.

But Network Rail insist that the Forth Bridge is not easy to access and that only determined trespassers, prepared to break the law, would attempt to do so.

The spokesman added: “The public won’t accidentally wander on to the bridge as you cannot reach it without effort – it has to be either climbed on to or crossed via the live railway. The only life at risk is their own – either through falling off or by being struck by a train.”

In his book – Explore Everything: Place-Hacking The City – Garrett reveals that he travelled with a group of friends from London last year to climb the structure under cover of darkness. They waited till 11pm to start their climb.

The group reached the very top then made their way across the entire 8000ft span of the bridge from North to South Queensferry as sleeper trains passed below.

Garrett writes: “Single-file, we began the slow traverse across, climbing down off the first platform and balancing precariously on beams just wide enough to support us.

“My heart was pumping furiously. A small list to the right and I’d fall 110m into the Firth.

“I knew that 63 men had died building this bridge and I couldn’t help but imagine their ghostly bodies plummeting through space and the feeling of helplessness I would experience if one of my friends fell.

“These thoughts were causing my whole body to burn with fear and excitement. This was serious edgework and I was high on it.”

They admit they struggled to cling on when it began to rain and had to speed up their progress for fear of slipping off.

Garrett adds: “Our last challenge was a run down the rail tracks to make our escape.

“ It was a run that might take about five minutes at top speed and, if a train came, we would certainly be seen and trigger a serious incident involving a herd of British Transport Police and an uncomfortable review of our video footage and photos.”

But when the Sunday Mail spoke to Garrett last week, he insisted that he had never been in any danger.

He said: “I don’t feel I was ever at risk. I wouldn’t do that, I wouldn’t put myself in that situation.

“In everyday life, you just don’t get the opportunity to climb down a beam on your hands and knees with a 200m drop beneath you.”

And he claimed he was constantly aware of the safety of others while balancing hundreds of feet above a passing train.

He said: “It’s certainly the case we need to be respectful and considerate of whether this causes complications for other people.

“But it’s much more likely that I would be hit by a bus while crossing the street than fall off the bridge.

“I know very few explorers who have been hurt and we’ve explored over 300 locations together.”

Twenty-two people have lost their lives in the past five years while trespassing on railways in Scotland and safety campaigners are outraged that such activities should be portrayed as a thrill-seeking hobby or a sight-seeing opportunity.

A spokesman for Trackoff, a rail industry initiative to help educate children and teenagers about safety, said: “Urban explorers accessing the railway in this way are trespassing, which is a crime and represents tremendous risk to the people involved. It’s a terrible example to young people.”

In the past decade, there have been only six known incidents of trespass on the Forth rail bridge, with four arrests.

British Transport Police said: “Trespassing on any part of the railway infrastructure is illegal and extremely dangerous.

“Trespassers put themselves, rail staff and passengers in danger."

But Garrett said many companies have thanked him for exposing failings in their security systems.

He added: “After we did the Shard, they hired 12 new security guards.”

Police Scotland said: “Any such incidents would be dealt with on an individual basis.”

Last year, rail chiefs revealed plans to erect a viewing platform at the top of the northern Fife tower, opening in 2015 to coincide with the bridge’s 125-year anniversary.

INVASION OF THE HYDRO

Garrett has also revealed that he managed to sneak into Scotland’s new arena – The Hydro – in January while on a birthday trip to Scotland with his girlfriend.

The couple took pictures of themselves in the Glasgow venue, which officially opens tomorrow night, before spending two hours wandering around the unfinished building.

Bradley Garrett inside the Hydro in Glasgow (Photo: Sunday Mail)

Then Garrett, along with artist partner Lucy Sparrow, slept in their car in a nearby car park.

He said: “It was about two in the morning and really cold at the time, which always helps as the security guards don’t like to wander about too much in the cold.